The invention relates to a method for the direction-dependent transmission of organization information in a cross-system channel, wherein the organization information relates to radio communication systems.
A continually rising number of different radio communication systems, examples mentioned being the systems based on the standards GSM, IS-95, UMTS, CDMA2000, WLAN (IEEE 802.11) and WiMAX (IEEE 802.16), is resulting in subscriber terminals also supporting an ever greater number of these systems and standards, and thus allowing the subscriber access to communication networks in a wide variety of ways. In addition, operators of radio communication systems are increasingly moving towards providing their customers with systems from different standards, with the option of roaming between these systems.
However, all this can disadvantageously result in the period for a subscriber terminal to set up a connection being extended on account of the large number of available systems, which also usually operate in different system-specific frequency bands. If the subscriber wishes to use, by way of example, a service with a high data rate, an example mentioned being video-streaming, then a service of this kind can potentially be provided by different systems. Provided that the subscriber has not preselected a specific system, during setup of the connection the subscriber terminal makes contact with various systems, or the subscriber terminal first of all attempts to receive signals from various systems—for example of the same operator—and then to select a system which is suitable for the chosen service.
Particularly if the subscriber terminal is started up at a location at which it has not previously been connected to a system and therefore cannot resort to practical values from previous connections, for example when the subscriber is abroad following a flight, the situation may also be aggravated or the access time extended by virtue of it not being known which local operator the home operator has made what is known as a roaming agreement with in order to provide customers with lower connection charges. In this case, the subscriber may repeatedly have a local system or operator proposed, for which the subscriber then needs to decide whether or not to set up a connection.
To provide subscribers or subscriber terminals with a clear overview of the growing number of systems, the document “Global Pilot Mechanism” Tdoc SMG2 UMTS 52/97, ETSI STC SMG2 UMTS adhoc, Apr. 8-10, 1997, Lulea, Sweden, pages 1 and 2, inter alia, has already proposed the introduction of a globally standard pilot channel (Global Pilot Channel) on a standard frequency channel or in a standard frequency spectrum. A global pilot channel of this kind should be used to transfer information about respective locally available radio access technologies (Radio Access Technology Indicator) and pointers (Spectral Pointer) to the spectral situation thereof, so that a subscriber terminal can select and access a suitable or supported radio access technology. In this context, radio access technologies are to be understood to mean systems from different standards, for example GSM and UMTS, which in turn operate in different frequency bands. According to the document above, the pilot channel should be transmitted either by the operators themselves, which accordingly would also need to transmit information from competing operators, or else by a national entity which is not specified in more detail, for example the regulating authority.
However, a globally standard pilot channel has the drawback that as the number of different systems and the expansion thereof to a larger number of frequency bands increases, the signaling load would likewise continually increase. Therefore, a subscriber terminal, having been referred by the pilot channel to the frequency spectrum of the GSM mobile radio system, for example, would also need to perform a large number of measurements for networks of different operators in order to ascertain a suitable operating network for the desired service or tariff or agreement.